Bumps changelog version to 1.15.0

Updates the CHANGELOG.md file to add a changelog entry for a new 1.15.0 version.

Author: laminas-bot

CHANGELOG.md

@@ -3,6 +3,28 @@
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
 
+## 1.15.0 - TBD
+
+### Added
+
+- Nothing.
+
+### Changed
+
+- Nothing.
+
+### Deprecated
+
+- Nothing.
+
+### Removed
+
+- Nothing.
+
+### Fixed
+
+- Nothing.
+
 ## 1.14.0 - 2022-07-25